1. Field of the Invention
This invention relates to an automatic focusing apparatus for a camera which meters an object light and automatically focuses a phototaking lens on the basis of the metering output, and more particularly to an automatic focusing apparatus suitable for use in a single lens reflex camera which meters the light passed through the phototaking lens and effects focus detection.
2. Description of the Prior Art
In an automatic focusing apparatus for a camera, there are two great desires to enhance the focusing accuracy and to increase the driving speed of the phototaking lens and quicken the focusing operation. In order to meet these desires, it has heretofore been proposed to decrease the driving speed of the phototaking lens when it lies within a predetermined in-focus range in the vicinity of the in-focus point and to increase the driving speed of the phototaking lens when it lies outside the predetermined in-focus range. However, it is not sufficient to vary the lens driving speed simply depending on whether the phototaking lens is within or outside the predetermined in-focus range. That is, where focusing operation is effected by metering an object light, if the object brightness is low, the responsiveness of the circuit is reduced and therefore, in such case, there occurs the necessity of decreasing the lens driving speed to obtain high focusing accuracy.